Mounting for inductance coils



Feb. 24, 1925. v 1,527,488

A. ONWOOD MOUNTING FOR INDUCTANCE COILS Filed May 10. 1923 Patented Feb. 24, 1925.

UNITED STATE S ANDRE; ONW'OGD, OF SOUlI-IIEH3119DS, ENGLAND.

MOUNTING FOR IN-DUCTANGE GOILS.

Application filed May 10,

To all whom it may, concern Be it known that I, ANDRE Oxwoon, a British subject, and; resident of 30v Hambledon Road, Southfields, London, S. W. 18, England, have invented certain new and useful Improvements in Mountings for Inductance Coil-s (tor which I have filed an application in England, dated 21st llune, 1922), of which the tollowing is. a specification.

This invention relates to apparatus for wireless signalling and, like purposes and particularly to the mounting of coupling coils and other inductance coils,

In wireless receiving apparatus it is often necessary to provide a tuning inductance in circuit with the aerial, a turther inductance in the secondary circuit coupled with the aerial and also. a reaction coil coupled with the other two coils. It is often desirable to mount all of these coils in a removable manner, so that when the range of wavelengths has to be chan ed these coils can be replaced by other interchangeable coils of ditt'erent inductance. Provision usually has to be made for varying the degree. of coupling between these coils and the arrangement most often used hitherto. for this purpose has been to hinge the coils together by means of a hinge arranged substantially in the plane oi? the adjacent faces of the two coils, in order to enable the coils to be adjusted from a relatively parallel position to a position relatively at right angles. \Vhen the coils are parallel the coupling is a maximum, but when they are moved into the position at right angles permitted by such an arrangement, the coupling is by no means reduced to zero; frequently it is only reduced to about per cent of the maximum value. Owing to this fact with such systems it is often diflicult to tune out from interfering transmitting stations.

It is one of the main objects of the present invention, therefore, to mount such coils so that the coupling can be varied from a maximum value to substantially Zero and for this purpose according to the invention, one coil is arranged to 'be fixed and the other coil is pivotally mounted so that it can be turned from a position close beside the fixed coil and parallel thereto in which the degree of coupling is a maxinuun into a position in which the degree of coupling has a zero or even a negative value. It is 1923. Serial No. 638,925

convenient to arrange the moving coil so that it can be turned into a position at right angles to the fixed coil with its mid plane coincident with the axis of the fixed coil, so that, in the latter position, the coupling is substantially zero.

In practice it is preferred to mount the moving coil or coils on the end of a pivoted arm which is. arranged so that when the two coils are parallel the angle betwen its cen tralplane and the central: plane of the fixed coil is made equal to 415 degrees. F or this result the movable coil has to be set obliquelyon the arm. so that its central plane is inclined l5 degrees to the central plane of the arm, 13y turning the arm, by means of a suitable handle through an angle of 90 degrees the moving coil takes up a position at right angles to the fixed coil and with its central plane passing through the axis of the fixed coil and in this position there is practically no coupling between the two coils. It is convenient to arrange two such coils, one on each side of the fixed coil and it is often necessary to make all three of these coils removable. A fixed coil may, for example, be plugged into. a socket on the fixed base and the moving coils each plugged into an insulating socket on its own pivoted arm.

In order that the invention may be clearly understood and readily carried into effect, it will be further described as applied.v to a three coil arrangement in connection with the accompanying drawings, in which Figure 1 is, a perspective View of the three coils andtheir mounting. 5

Figure 2 is a plan of the same, and

Figure 3 is a further plan showing the coupling between the fixed coil and the two movable coils altered.

In these drawings a is the fixed coil and it has a moving coil 7) and 0 one on each side of it. Such an arrangement is useful in wireless telegraphy receiving instruments where, for example. the coil a may be the tuning inductance in the secondary closed circuit, the coil 7) the aeial tuning inductance and the coil 0 the usual reaction coil intended to be connected in the anode circuit of one of the thermionic valves of the receiving instrument in the usual manner. The coils are shown mounted in a shallow box (Z with an ebonite top 6. The central coil a is shown detachably mounted on an insulating socket 7. For this purpose it is furnished with two terminal pins (not shown) which engage in conducting sockets V in the base tral planes inclined at angles of 45 degrees V to the central planes of the coils b and 0 respectively as can be seen clearly in Figures 2 and 3. The pivots of the arms 9 and 71 are seen atk and m. Theoretically, the pivots 7s, 711, should lie in line with the outer edges of the coils a, Z), 0 when the latter are all close together and parallel but, as shown, the pivots are placed slightly within these lines. By means of this arrangement, the arms'g and h are slightly shortened and the whole apparatus is made rather more compact. The only disadvantage is that when either of the moving coils is turned from the position of coil 6 in Figure 2 during the first movement the edge of the coil tends to move slightly towards the fixed coil, which means that the coils can. notapproach as closelyas they might otherwise. The adjusting arms 'n and 0 which are of insulating .material, preferably of ebonite, are secured to the pivots 7a, m and are long enough so that no capacity efiects of practical importance are introduced by the hand of the operator in turning the coils. The coil 7) in Figure 2 is shown in the position of maximum coupling with the central plane of the arm at an angle of degrees to the central plane of the fixed coil a. In Figure 2 the coil 0 is shown in the position of minimum coupling and in Figure 3 the coil Z2 has been moved. to the corresponding position, while in that figure the coil 0 is shown in an intermediate position. The arms g and h co-act with stop pins 10 and g which allow the coils b and 0 to be turned parallel to the coil a in one extreme position and in the other extreme position allow the coils to pass slightly beyond the position of zero" coupling, so that a negative coupling of a small magnitude can be obtained. The three coils are illustrated with terminals 1), 72 a, a 0, 0 respectively. In order to enable the moving coils to be connected to their terminals, the arms 9 and h each have aflspring strip brush fixed to their under-sides and bearing upon a contact seg- V ment 1", s; the other terminal may be con nected through the pivot spindles is, m.

As shown, the arms 9, h are arranged with their central vertical planes inclined at 45 degrees to the central planes of the coils b, 0 respectively. It is possible, however, to mount the coils on' their arms at a difierent angle. If the angle is lessthan 45 deright angle to be moved fromthe position Similarly, if the to be turned throughan angle less than a of maximum coupling into the position of 7 zero coupling.

With the three coils mounted as shown and with independent terminals, it is clear that they may be used in a wireless teleg- 'raphy receiver of the coupled type with re-' action coupling as already mentioned, bulit is clear that such coils may be used as a variometer or variable inductance,

though usually in such a case only one moving 0011 will be necessary and in that case the moving coil and fixed coil would be connected in series or parallel asthe case may be; 'The coils illustrated in the drawlng are high efficiency coils as set forth and claimed in my patent application Serial 7 No. 620,095 filed 19thFebruary 1923, but it is clear that the invention can "also be employed in conjunction with any" other former inductance coil.

Having thus described my invention what Iclaim as new and desire to secure by Letters Patent is 1. In a mounting for inductance coils,.a

support, a coil holder fixed thereto and adapted to carry a fixed coil, a pivot mounted on said support with its axis parallel to the plane of said fixed coil and a movable coil holder mounted to turn about said pivot and adapted to carry a movable coil disposed so that'the planes of its faces al-.

ways remain parallel to those of said fixed moving coil;

2. A\mounting for inductance coils in- V cluding a supporting base, a coil holder 'fixed thereto, a fixed coil carried by'said coil holder, a pivot mounted on said base with its axis parallel to the planes of the faces of said fixed coil, a movable coil holder mounted to turn about said pivot and a movable coil rigidly carried by said movable coil holder in such a position that said pivot lies substantially out of the plane-of said movable coil. i

3. In a mounting for inductance coils, the combination of a support, a coil holder fixed thereto and adapted to carry a fixed coil,'apivot mounted on said support and lying with its axis parallel to the plane of said fixed coil and a movable coil holder mounted to turn about said pivot and adapted to carry a movable coil in such a position that said pivot lies substantially out of the plane of said movable coil, said movable coil holder. being capable of free movement to move said movable: coil from a position parallel to and beside said fixed coil to a position at right angles to and lying in the axis of said fixed coil.

4. In a mounting for inductance coils a support, a pivot upstanding therefrom, a coil holder fixed on said support, terminals carried by said coil holder adapted to maintain a fixed coil detachably in a plane parallel to the axis of said pivot, a movable coil holder mounted to turn about said pivot and terminals carried by said movable coil holder adapted to secure detachably a movable coil in such a position that the axis of said pivot lies substantially external to the planes of said movable coil.

A mounting for inductance coils inchi ding a supporting base, a coil holder fixed thereto, a fixed coil carried by said coil holder, a pivot mounted on said base to lie parallel to the plane of said fixed coil but substantially out of said plane, a movable arm mounted to turn about said pivot and a movable coil carried by said arm with its plane inclined to the central axis of said arm.

6. A mounting for inductance coils including a supporting base, a coil holder fixed thereto, a fixed coil removably attached to said coil holder by conductive plug and socket connection, a pivot mounted on said base to lie parallel to the plane of'said fixed coil but substantially out of said plane, a movable arm mounted to turn about said pivot and a movable coil attached by said arm by conductive plug and socket connection so that its plane is inclined to the cen tral axis of said arm.

7. In a mounting for inductance coils a support, a coil holder fixed thereto, a pair of pivots mounted on said support to lie on opposite sides of the plane of the fixed coil but parallel to said plane and a pair of movable coil holders, each mounted to turn about its respective pivot and each adapted to support a movable coil in such position that the respective pivot lies substantially out of the plane of the said movable coil.

8. A mounting for inductance coils i11- cluding a supporting base, a coil holder fixed thereto, a fixed coil carried by said coil holder, a pivot mounted on said base, to lie substantially out of the plane of said fixed coil but parallel to said plane, a pivotal arm mounted to turn about said pivot, an insulating operating handle operatively connected with said arm to turn therewith and a m'ovable coil carried by said arm.

9. A mounting for inductance coils including a supporting base, a coil holder fixed thereto, a fixed coil removably at tached to said coil holder by conductive plug and socket connection, a pivot mounted on said base to lie parallel to the plane of said fixed coil but substantially out of said plane, a movable arm mounted to turn about said pivot and a movable coil attached by said arm by conductive plug and socket connection so that its plane is inclined to the central axis of said arm at an angle of substantially degrees.

10. In a mounting for inductance coils a support, a supporting base, a coil holder fixed thereto, a pair of parallel socket terminals mounted in said coil holder, a pivot mounted on said base to lie parallel to the plane passing through said socket terminals, a movable coil holder mounted to turn about said pivot and a pair of parallel socket terminals mounted in said movable coil holder in such position that said pivot lies substantially out of the plane passing through said last-mentioned socket terminals.

11. In a mounting for inductance coils a fixed support, a coil holder fixed thereto, a fixed coil rigidly carried by said coil holder, a pivot mounted upon said support, a movable coil holder mounted to turn about said pivot and a movable coil rigidly carried by said movable coil holder in such a position relatively to said pivot that the latter is parallel to the planes of the faces of said moving coil but is situated substantially to one side of the space lying between these planes and substantially to one side of the axis of said moving coil, said pivot also being located so that during the turning movement of the moving coil the latter moves from a position of maximum coupling close beside the fixed coil and parallel thereto into a position in which the coupling between the said two coils has a relatively negligible value.

12. A mounting for inductance coils including a supporting base, a coil holder fixed thereto, a fixed coil carried by said coil holder, a pivot mounted on said base situated substantially to one side of the space lying between the planes of the faces of said fixed coil, a movable coil holder mounted to turn about said pivot, a movable coil carried by said movable coil holder and a relatively long operating arm of insulating material mounted also to turn about said pivot and clamped to said movable coil holder.

In witness whereof, I hereunto subscribe my name this 30th day of April, A. D. 1923.

ANDRE ONIVOOD. 

